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31.
Angela Lombardi Michele Saviano Flavia Nastri Ornella Maglio Marco Mazzeo Carlo Pedone Carla Isernia Vincenzo Pavone 《Biopolymers》1996,38(6):683-691
In the present paper we describe the synthesis, purification, and single crystal x-ray analysis of the cyclic pentapeptide cyclo-(Pro-Phe-Phe-β-Ala-β-Ala). This compound crystallizes in the orthorhombic space group P212121 from methanol and adopts in the solid state an unusual conformation characterized by a cis β-Ala5-Pro1 peptide bond and by an intramolecular hydrogen bond stabilizing a C11- and a C12-ring structure. The C11, structure contains the Phe3 and the β-Ala4 at the corner position of the turn; it is the first observation of a type II β-turn enlargement due to the insertion of an extra methylene group of the β-alanine residue. The rest of the molecule participates in a newly characterized C12-ring structure, which incorporates a β-Ala residue at position i of the turn. © 1996 John Wiley & Sons, Inc. 相似文献
32.
Carlo V. Bruschi John N. McMillan Maristella Coglievina Michael S. Esposito 《Molecular genetics and genomics : MGG》1995,249(1):8-18
When diploid cells of Saccharomyces cerevisiae homozygous for the temperature-sensitive cell division cycle mutation cdc6-1 are grown at a semipermissive temperature they exhibit elevated genomic instability, as indicated by enhanced mitotic gene conversion, mitotic intergenic recombination, chromosomal loss, chromosomal gain, and chromosomal rearrangements. Employing quantitative Southern analysis of chromosomes separated by transverse alternating field gel electrophoresis (TAFE), we have demonstrated that 2N-1 cells monosomic for chromosome VII, owing to the cdc6-1 defect, show slow growth and subsequently yield 2N variants that grow at a normal rate in association with restitution of disomy for chromosome VII. Analysis of TAFE gels also demonstrates that cdc6-1/cdc6-1 diploids give rise to aberrant chromosomes of novel lengths. We propose an explanation for the genomic instability induced by the cdc6-1 mutation, which suggests that hyper-recombination, chromosomal loss, chromosomal gain and chromosomal rearrangements reflect aberrant mitotic division by cdc6-1/cdc6-1 cells containing chromosomes that have not replicated fully. 相似文献
33.
Gianfranco Tucci Marco Cosimo Simeone Carlo Gregori Fabio Maggini 《Plant Systematics and Evolution》1994,190(3-4):187-193
Intergenic spacers of the rRNA genes of three species of theCynareae tribe:Cynara cardunculus subsp.scolymus (artichoke),Onopordum acanthium, andO. illyricum were cloned in the plasmid pGEM-7zf(+). Detailed restriction mapping and partial sequencing of the IGSs were carried out. The structural analysis showed a clear diversity betweenCynara andOnopordum, while a high degree of homology was found between the twoOnopordum spp. In all three species a fragment of about 450 bp from the 5 end of 18S to the Acc I site with a high sequence homology was present. Nucleotide sequences upstream from the above mentioned Acc I site show a gradual decrease of homology betweenCynara andOnopordum. 相似文献
34.
This review compares published surveys of microbial populations in plant tissue and cell cultures with the microbial saprophytes and pathogens found on field grown plants and microbial populations in the laboratory environment. From this comparison and the measured reduction in contamination after improvements in working practices in the laboratory, conclusions can be drawn about the importance of the explant and the laboratory as sources of contamination.
Mechanisms of pathogenicity in vitro are described to explain why bacteria, fungi, and yeasts that are not pathogenic to plants in the field become pathogens in plant tissue cultures. Conversely, plant metabolism and its effect on the tissue culture environment are described to explain why prokaryotes, viruses, and viroids that cause disease in the field can stay latent in vitro.
Detection methods for latent contaminants in plant tissue cultures are summarized, and the strategies and methods for prevention or treatment of contamination are discussed. 相似文献
35.
David H. Rosenblatt John F. Manning Jr Carlo D. Montemagno 《Soil & Sediment Contamination》1994,3(1):1-27
Plans are being formulated for in situ bioremediation of a subsurface plume of diesel fuel No. 2 that resulted from an accidental fuel release. Raoult's law and the aqueous solubilities of the toxic components were used to estimate organic contaminant concentrations in leachate from the untreated fuel mass. Carcinogenic risks and noncarcinogenic hazard indices were calculated for undiluted leachate. An 80% decrease in hydrocarbon mass and increases in the average molecular weights of the component fractions were assumed to result from the treatment. Sample calculations are provided to show how to evaluate results of analyses for petroleum hydrocarbons after bioremediation. 相似文献
36.
Even Amler Nelvio Cester Eleonora Salvolini Roberto Staffolani Martin Burkhard Laura Mazzanti Arnot Kotyk Carlo Romanini 《Cell biology international》1994,18(7):723-727
Placentas of women suffering from pregnancy-induced hypertension (PIH) were found to contain a greater amount of Na,K-ATPase molecules, estimated from anthroyl ouabain binding, than normotensive individuals. Both the microsomal fraction of placental cells and purified Na,K-ATPase showed an increased affinity for the specific inhibitor ouabain which, in the case of the microsomes, bound with a dissociation constant of 0.9 nM as compared with 3.4 nM in the controls. Likewise, the dissociation constant of the ouabain complex with purified Na,K-ATPase was about 3.5 times lower in the hypertensive patients. The differences are apparently caused by a different microenvironment of the ouabain-binding site, as reflected in the quantum yield of bound anthroyl ouabain. If an endogenous digitalis-like factor is present in the body fluids to regulate Na,K-ATPase activity, the present results render its role quite plausible. 相似文献
37.
Carlo Capelli Guglielmo Antonutto Paola Zamparo Massimo Girardis Pietro Enrico di Prampero 《European journal of applied physiology and occupational physiology》1993,66(3):189-195
The mechanical power (Wtot, W·kg–1) developed during ten revolutions of all-out periods of cycle ergometer exercise (4–9 s) was measured every 5–6 min in six subjects from rest or from a baseline of constant aerobic exercise [50%–80% of maximal oxygen uptake (VO2max)] of 20–40 min duration. The oxygen uptake [VO2 (W·kg–1, 1 ml O2 = 20.9 J)] and venous blood lactate concentration ([la]b, mM) were also measured every 15 s and 2 min, respectively. During the first all-out period, Wtot decreased linearly with the intensity of the priming exercise (Wtot = 11.9–0.25·VO2). After the first all-out period (i greater than 5–6 min), and if the exercise intensity was less than 60% VO2max, Wtot, VO2 and [la]b remained constant until the end of the exercise. For exercise intensities greater than 60% VO2max, VO2 and [la]b showed continuous upward drifts and Wtot continued decreasing. Under these conditions, the rate of decrease of Wtot was linearly related to the rate of increase of V [(d Wtot/dt) (W·kg–1·s–1) = 5.0·10–5 –0.20·(d VO2/dt) (W·kg–1·s–1)] and this was linearly related to the rate of increase of [la]b [(d VO2/dt) (W·kg–1·s–1) = 2.310–4 + 5.910–5·(d [la]b/dt) (mM·s–1)]. These findings would suggest that the decrease of Wtot during the first all-out period was due to the decay of phosphocreatine concentration in the exercising muscles occurring at the onset of exercise and the slow drifts of VO2 (upwards) and of Wtot (downwards) during intense exercise at constant Wtot could be attributed to the continuous accumulation of lactate in the blood (and in the working muscles). 相似文献
38.
Carla Caruso Carlo Caporale Elia Poerio Angelo Facchiano Vincenzo Buonocore 《Journal of Protein Chemistry》1993,12(4):379-386
The amino acid sequence of wheatwin1, a monomeric protein of 125 residues isolated from wheat kernel (variety S. Pastore), is reported. Wheatwin1 is highly homologous (95%) to barwin, a protein from barley seed, which was shown to be related to the C-terminal domain of two proteins encoded by the wound-induced geneswin1 andwin2 in potato and to a protein encoded by the same domain of the hevein gene (hev1) in rubber tree. Similarly to barwin, wheatwin1 contains six cysteine residues all linked in disulfide bridges and the N-terminal residue is pyroglutamate. Moreover, structural studies performed on wheatwin1 andwin1 protein by predictive methods demonstrated that these proteins and barwin are closely related in the secondary structure also. The high level of homology found with the product ofwin1,win2, andhev1 genes strongly suggests that barwin and wheatwin1 play a common role in the mechanism of plant defence. 相似文献
39.
Kay Huebner Teresa Druck Sal LaForgia Jerzy Lasota Carlo M. Croce Luisa Lanfrancone Emilio Donti Gina Pengue Girolama La Mantia Pier-Giuseppe Pelicci Luigi Lania 《Human genetics》1993,91(3):217-222
cDNA clones encoding zinc finger motifs were isolated by screening human placenta and T-cell (Peer) cDNA libraries with zinc finger (ZNF) consensus sequences. Unique cDNA clones were mapped in the human genome by rodent-human somatic cell hybrid analysis and in some cases in situ chromosomal hybridization. ZNF 80 mapped to 3p12-3qter, ZNF 7 was previously mapped to 8q24 and is here shown by in situ hybridization and use of appropriate hybrids to map telomeric to the MYC locus. ZNF 79 mapped to 9q34 centromeric to the ABL gene and between a constitutional chromosomal translocation on the centromeric side and the CML specific ABL translocation on the telomeric side. ZNF77 mapped to 19p while ZNF 78L1 (pT3) mapped to 19q. Chromosome 19 carries many ZNF loci and other genes with zinc finger encoding motifs; the pT3 clone additionally detected a locus designated ZNF 78L2, which mapped to chromosome region 1p, most likely in the region 1p32 where the MYCL and JUN loci map. 相似文献
40.
Carlo Severi 《The journal of the Royal Anthropological Institute》2004,10(4):815-838
With few exceptions, it has been assumed that the production of a generalizing anthropological theory of human cognition must necessarily entail a reduction of ethnographic complexity. No case-centred analysis has been offered to show that a cognitive approach to cultural complexity is possible. In this article, I want to show that a different cognitive perspective can improve our understanding of ethnographic facts and help us critically to revise a number of traditional anthropological concepts. In order to do so, I will discuss the example of a messianistic religious movement born among the Western Apache of San Carlos and White Mountain (Arizona). 相似文献